LeanGantt provides a set of functions for managing Gantt charts in Google Sheets™. It aims to simplify the process of creating and maintaining Gantt charts by automating task dependencies, data validation, and error handling.

Key Features:
- Task Dependencies: Automatically updates the start and end dates of tasks based on their predecessors and duration.
- Data Validation: Validates the start date, end date, duration, and predecessors of tasks to ensure data integrity.
- Circular Dependency Detection: Prevents the creation of circular dependencies in the task relationships.
- Error Handling: Displays informative error messages when invalid data is entered and reverts to the previous value.
- Additional Features: Includes functions for calculating working days, adding or removing working days from a date, and getting the latest predecessor's end date.